Basic achievements of social development lie in the child's attainment of the interactive skills which enable him to become a progressively more adept partner in generating the patterns of interaction characteristic of human social encounters. This proposal is guided by a model of infant social development that stresses the continual interplay between the infant's experiences in social interaction and his attainment of interactive skills. The primary aims of the research are: (1) to describe the patterns of interaction infants generate with others, (2) to discover the interactive skills of the infant that contribute to such patterns, and (3) to understand how each skill originates in development and how each functions to mold still further development. Study 1 examines the attempts of 12 pairs of peers, either 18- or 24-months of age, to generate social interaction; whatever interaction peers manage must be attributed to the skills of children their age. Observers record predefined behaviors from videotaped records, generating a sequential listing of each child's behavior along a common time line. Analyses explore temporal correspondences between the two children's behaviors. Study 2, a longitudinal inquiry, traces the developmental course of the skills discovered in Study 1; the sequence in which the skills emerge and the social contexts in which they emerge are assessed. Thirty infants are observed at 16-, 20-, 24-, 28-, and 32-months of age interacting with their mother, an unfamiliar woman, and a peer. Study 3 traces in finer detail the emergence of social skills from 24 to 30 months, an age span of anticipated major changes in skills.